in recent years, a display device using organic EL is drawing attention as one of next-generation flat panel displays as a substitute for liquid crystal display devices. Active-matrix display devices such as display devices using organic EL include thin-film transistors (TFTs) as drive transistors in respective pixels of the display devices.
In a drive transistor including a TFT, a threshold voltage shifts due to voltage stress such as a gate-source voltage when a current is applied. In addition, a shift amount of the threshold voltage differs from pixel to pixel included in a display device. The shift of the threshold voltage causes a variation in an amount of current supplied to an organic EL element. Thus, this may affect luminance control of the display device, and degrade display quality.
A technique is known which, in order to compensate a threshold voltage of a drive transistor, applies to the drive transistor a compensation voltage for compensating the threshold voltage, in a period other than a period in which a video signal voltage is applied to the drive transistor (for example, Patent Literature (PTL) 1).